i have same experiences about power, engine becomes fully alive after 4000rpm, below that if you try to accelerate in ordinary trafic with 4th gear, acceleration is nothing special. Now weather here has been cold and humid due rains, and i have been able to activate asr easily when starting gear 1. Things under the hood get very hot even you drive 100 km/h, hot air cannot get easily out from engine compartment. Try air filter assy, intake air tubing,everything gets so hot. No wonder that power is lost in hot climate, because engine cannot draw cool air inside.
I will make a test and remove plastic cover under the engine and try to measure if engine and air intake is cooler. This is not of course cure to base problem, but anyway route to find pittfalls in MB design....Hm, i'm starting to think that this car needs intercooler and supercharger.

I happen to have the lower engine encapsulation panel removed right now, as I fixed an oil leak recently (new oil pan gasket) and wanted to easily inspect after driving a few hundred miles to make sure it was stopped. Doesn't seem to matter if the panel is on or off, though, as far as power is concerned. I'll be re-installing the panel as soon as my tranny cooler line arrives and I replace that, along with changing the ATF to Mobil-1.

About the airbox, here's an interesting item I just picked up, it's an airbox shielded with space-age insulating material:

http://500ecstasy.com/forums/showthread.php?t=814

My IR thermometer showed the stock airbox top surface was in the 150F range with the engine warm! Yipes. And that was with ~80F ambients. I'm curious how much heat the insulation/foil will reject. That only reduces intake air temp, but I'll take anything at this point.

About the low-end power. My OM603 turbo diesel seems to be snappier down low, say 2000-2500rpm, and it shouldn't be - the M119 is rated at lots more torque, even off idle. That's why I'm suspecting the camshaft advancers aren't advancing, they advance in the low RPM range to boost power, then retard at high RPM (retard is the default/normal position for starting and idle as well). The cam timing data is in the intro manual, IIRC, I just looked at it a couple weeks ago - I'll find it again and post the numbers here, as someone else questioned this earlier.

Problem is, I have ZERO idea how to measure cam advancement (or lack thereof!) with the engine running. If the solenoids just get a plain 12VDC signal, I guess I could connect a bulb in parallel and run it into the interior and go for a drive, and see if it lights up at the RPM range specified in the manual? That wouldn't prove the solenoid(s) were working internally, but would eliminate the computer & electronics as an issue (for cam timing anyway).

What's your oil pressure when idling, engine completely heated up? My is 1.5bar when N, and when D 1 bar. When engine runs 1200 rpm, full oil pressure. Just asking because oil pressure is used to turn cam timing gear.
I don't have clue how cam is advanced or retarded vs rpm. Do you have such graph? If timing is adjusted linearly, i think solenoid is driven by PWM signal, square wave voltage, duty cycle is adjusted to give certain force to let oil to turn timing gear.
With bulb you can see lightness change, but best tool is oscilloscope or multimeter with duty cycle or frequency counter.
I could measure from my car what kind of waveforms i got.
This is just a guess, but this i the way normally hydraulic servo valves are controller, and is probably used here also.
About your om 603, has there been any tuning around these diesel engines in US? It is increasing here, because of tractor pulling, diesels as well. You can squiz over 400 hp from this 3liter diesel engine for street use without major modifications to engine itself. sorry stepping side about subject.

My car came with Mobil-1 of unknown weight from the PO, and was about 1.1bar hot idle, rising to 3 bar off idle (probably the same ~1200 rpm). I just changed the oil and filled with the new Mobil-1 5W-40 weight (Delvac-1), now hot idle pressure is a little higher, around 1.4-1.5 bar, which makes me think the previous stuff might have been 10W-30. Zero change in performance but I prefer the 5W-40 weight.

I believe the cam timing is an on/off affair, not variable. Something like it goes adavanced by 5 degrees or so at ~1500rpm, then back to normal (retarded) around 3500rpm, or something like that. I have the exact numbers at home. The PWM idea is interesting, I wonder if that's what's going on...? Hmmm.

My 603.960 (1987 300D) is mostly stock but I am VERY interested in getting more power from it - safely! - for street use. I'd be thrilled with 180-200hp (up from 148 stock). Mosselman makes an intercooler kit good for 20% gain (175hp) but the cost is steep, about $1800 USD thanks to the poor exchange rate. If you have any specific info on souping up the OM603 turbo, please let me know!

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About 300D turbo power increase, stock kkk turbo is too small for anything, and you need to add intercooler. If you just add cooler, with stock turbo and adjusting the fuel injection pump you can get 180. Before doing anything, add cooler first! Hot intake air will kill cylinder head.
After fitting good cooler, you can make hybrid turbo to old body of stock one, fit bigger wheels inside etc to raise boost pressure and airflow. And then, most expensive thing, modify fuel injection pump to increase fuel feed. Stock pump will limit power under 200 hp and injection time is too long for high performance. Of course bigger exhaust. Nicest thing to all, no need to open engine/modify, etc. Stock will take almost anything. Transmission is also very strong in turbo d, and if you want more safety margin, you can add more clutch plates inside gearbox


If you do all things all the way as i described....easily 350hp. 500E will have hard time to catch up...record here now for street car is now 432hp/570nm or so.

Wow... damn. My plan was to leave the turbo stock, add an intercooler somehow, and turn up the full load screw inside the otherwise stock injection pump. I'd be happy with ~180hp, and I'd like to retain decent economy (30mpg is nice!) for freeway cruising, which should be OK with just an intercooler, right? I was thinking of removing the catalyst from the exhaust (USA models added a cat in the main downpipe, under the passenger's feet) but wasn't sure if that would gain any power or not. I turned up boost from 12psi to 15psi but there was no power gain, probably need to tweak the pump a bit, but can't go far without an intercooler. Any photos / websites with more info on 603 mods??

Stupid question - where should IP timing be set for best power? I find that economy improves when set at 13.5-14.0 (spec is 15.0, +/- 1.0) but I wasn't sure if that was best for power gains.

I thought I saw this in the Intro manual, but nope, it was in Stu Ritter's 'E-Class Owner's Bible', page 149:

Engine RPM -------- Position ---------- Effect
==================================
Engine off ----------- Retarded ---------- Good starting

0-2,000rpm ---------Retarded ---------- Improved idle & cylinder filling

1,500-4,700 rpm ---- Advanced -------- Increased torque, reduced fresh charge loss

4,700-redline -------- Retarded --------- Improved volumetric efficiency

"The adjuster rotates the camshaft by 25 degrees between the default retarded position and the advanced position, relative to crankshaft rotation. The adjustment takes about one second to complete."

Stock om603 smoke hardly att all, so only adding more boost don't help much, as you noticed. More fuel is needed also. Removing cat is good thing to do. At least turbo spin up fasted with reduced backpressure. When increasing feed from pump, normally timing is advanced a bit, 5 deg or so.

About timing of cams, there is sensors for cam timing in both heads. I think they are there to measure timing change. I wonder is there error code in the computer to tell if cam adjusting don't work.

Can you suggest good material for reading about 500E, what kind of material there is available from MB itself?

You are correct, there are sensors for the cams. I was wondering if they need to be cleaned, someone else in a different thread on this forum had them "de-glazed" along with whatever part the sensors sense, which fixed their problem. Dunno if codes are generated or not.

For 500E information, there are some websites out there, or you could try to find one of the factory "Intro" manuals like this one:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7909290576


PS: I want to turn up the 603 fuel just a hair, maybe 1/4 turn on the full load screw, and see what that does... don't want to go any further without intercooling though! :p

Sensors are magnetic so i think that cleaning don't do anything good. In cam mechanism there is toothed wheel which magnetic sensor "detects". And if signal from sensor is not good, i think computer will tell it right away. Haven't yet measured signals to magnetic actuator...try to do it weekend.
Well, i'm not too keen to hunt original manuals. Just if i could get copies of all relative material...maybe somebody here could help...

Greetings Dave- hope this issue gets resolved!

fwiw- I recall from a Hot Rod Forum post ~24 mos ago:
... of an E500 owner whom indicated that he was getting rid of his 124.036 and observed power/tq decrease over the life of his deemed healthy '94 E500.

I believe he also shared that he's owned 3 different 124.036's and was moving toward a 400HP Jag type R as his incoming replacement.

Have you had a detailed chat yet with Carl at Bergwerks, Donnie from MB Autowerks, M.B. Doc, Bruce Strauss in S Cal, Steve Brotherton of Continental Imports, or any techs here on this board regarding testing procedures and proper operation of the cam advance for your ''94?

-fad

Carl replied to my post over on the 500E.com forum (linked earlier in this thread), but haven't heard from him since then. He thinks my elevation (2400ft) is part of the problem, which it may be, but I think there's something else amiss. I'm hoping a dyno run might shed some light on things. If the cams are advancing normally, then I'm really stumped...

Dave, what was the outcome ?

:-) neil

Woops - forgot to update this thread! Better late than never, eh? Basically, it was a non-issue... extensive dragstrip testing has proven that the car is running normally for a 500E, at my elevation (2700'). At a sea level dragstrip, it was faster (as expected), and I also had traction problems when launching... indicating improved low-end power at lower elevation.

However, the temperature-related power drop remains... when the engine is cold to cool (say, 50-70°C on the dash gauge) the car will spin the tires much more easily. At 90°C and up, it will only spin the tires if ambient temps are fairly low (say, under 60°F). When I originally started this thread it was in the middle of summer heat (July) and the car pretty much refuses to spin the tires in summer, unless engine temp is ~60°C. I wish there was a way to produce that "extra" power at normal operating temps (80-100°C) but I doubt that will happen as long as the LH engine management system is in control. I believe this is "normal" and there's probably nothing wrong with my car. (If yours will fry the tires on a hot summer day with no problems... then maybe I do still have something wrong! )

Hope that helps - let me know if you have any more questions. I'm still planning on a dyno run.

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See post #10 and 15...